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N. EINER-JENSEN

Exchange of the inert gases 85krypton and 133xenon between the testis and the caput and corpus epididymidis on the ipsilateral but not on the contralateral side has recently been demonstrated in rats. The exchange was probably based on a countercurrent exchange of the gases between the internal spermatic vein and artery (Einer-Jensen, 1974). To investigate if testosterone could be transferred by the same mechanism, the following experiment was performed.

Twenty-four 5- to 6-month-old Charles River male rats were used for the experiment. They were previously used for mating purposes about twice a week.

The animals were anaesthetized with an intraperitoneal injection of 30 mg Mebumal-Na (Nembutal®)/kg. The abdomen was opened through a midline incision, the right testis and the epididymis were withdrawn into the abdomen for injection of 0·2 μg (30 μCi) [1,2-3H]testosterone (N) (New England Nuclear, NET 187) dissolved in 0·1 ml ethyl alcohol benzene

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N. EINER-JENSEN

In the male, a countercurrent mechanism between vena and arteria spermatica interna seems well documented. The exchange has been described for heat (Waites, 1970), inert gases (Einer-Jensen, 1974a) and for testosterone (see Setchell, 1973; Einer-Jensen, 1974b).

In the female, much less evidence exists for a similar exchange between the cranial uterine and ovarian blood vessels, although the vessels are close together in many species including sheep, horses, cattle, pigs, rats, rabbits and guineapigs (see Goding & co-authors, 1972). So far, a local exchange has only been described with 133xenon in sheep (Coudert, Phillips, Faiman, Chernecki & Palmer, 1974a) and with prostaglandin F in sheep (McCracken, Baird & Goding, 1971; McCracken & co-authors, 1972) and cattle (Hixon & Hansel, 1974).

Using a method similar to the one indicating recirculation of the inert gases, 133xenon and 85krypton, in the male countercurrent system (Einer-Jensen, 1974a), the present experiment was

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N. EINER-JENSEN

Summary.

In the rat, the arteries supplying the testis and the caput epididymidis originate in the internal spermatic artery, and the blood vessels to the cauda epididymidis originate in the vasal artery.

This anatomical configuration may explain results obtained in experiments in vitro showing that gas originating from injections of saline solutions of 133xenon and 85krypton into the testis was found within 60 sec in the caput epididymidis but not in the cauda or in the same contralateral organs.

In experiments in vivo using 85krypton and a microminiature Geiger-Muller tube placed inside the organs, the same type of recirculation was indicated, as well as recirculation from the caput epididymidis to the testis. Ligation of the ductuli efferentes does not change the observation.

Radioactivity increased during the first five min after the injection. The washout of the gas was slow: 94% to 75 % of the initial activity remained after 25 min.

Both types of experiments support the hypothesis that exchange of gas, like that of heat, can take place in a countercurrent system formed by the pampiniform plexus and the internal spermatic artery.

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N. Einer-Jensen

In the rat, total uterine blood flow is maximal during peak secretion of oestrogen (Spaziani & Suddick, 1967; Greiss & Anderson, 1973). This is probably due to a high rate of flow through the myometrium, since endometrial blood flow has been shown to be twice as high during dioestrus as during oestrus (Einer-Jensen, 1976). If the high endometrial blood flow in dioestrus is associated with progestagen secretion, a high endometrial blood flow in early pregnancy would be anticipated. This supposition was examined in the present study.

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N Einer-Jensen and RHF Hunter

Heat and substances, including gases, steroids and peptide hormones, can pass from venous blood, interstitial fluid and lymph to the arterial blood; the process is called local counter-current transfer. It has been found in various reproductive organs in many animal species and in man: from the testis to the testis and epididymis; from the ovary to the ovary, tube and tubal corner of the uterus; from the tube and uterus to the ovary; from vagina to uterus; and even between brain blood vessels. Local transfer within the ovary has also been found. Local cooling that creates temperature gradients between organs or within an organ is one aspect of the transfer. Physiologically, the transfer also facilitates local feedback regulation of organ function in a process situated between general distribution of hormones through the systemic circulation and paracrine regulation. Counter-current transfer of drugs after local application opens up new possibilities for treatment.

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N. EINER-JENSEN and N. J. SECHER

Summary.

Daily treatment for 3 to 9 days with 3 to 12 mg/kg haloperidol (4-[4-(p-chlorophenyl) -4-hydroxypiperidino] -4′ -fluorobutyrophenone) given by stomach tube to pregnant rats delays the growth of the foetuses, if treatment is started on the day of copulation (Day 0) or the day after. The delay is not seen if treatment is started on Days 4 or 7. If 3 to 9 mg/kg haloperidol is administered on Day 1 to Day 16, the young are normal in appearance at birth, but with 1 to 6 days' delay. These findings could indicate that implantation is initiated earlier than is generally accepted.

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W. Schramm, N. Einer-Jensen and G. Schramm

Summary. 125I-labelled relaxin and tyrosine were infused into the ovarian vein to investigate transfer to branches of the ovarian artery at the ovarian pedicle in sheep. The ovarian arteries supply the ovary, the oviduct, and the tip of the uterine horn. An exchange of relaxin (n = 24) and tyrosine (n = 18) was observed in blood samples collected from all branches of ovarian arteries. This is expressed as a ratio of radioactivity > 1 between jugular venous blood plasma and arterial blood plasma. The average ratio ( ± s.d.) over the total infusion period of 1 h was 1·42 (± 0·35) for relaxin and 1·69 (± 0·38) for tyrosine with maximal values up to 4·9 and 2·9, respectively. Of the total amount of substance infused (348 pmol/h), 0·22% of the relaxin and 1·19% of the tyrosine reached the adjacent arteries directly. From these investigations it is concluded that (a) molecules with a molecular weight of ∼ 6000 can be transferred directly from veins to arteries at the ovarian pedicle, and (b) the efficiency of this exchange does not only depend on molecular size.

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G. M. H. WAITES and N. EINER-JENSEN

Department of Physiology and Biochemistry, The University, Reading RG6 2AJ, and The Population Council, The Rockefeller University, York Avenue and 66th Street, New York, NY. 10021, U.S.A.

(Received 6th September 1974)

Testicular spermatozoa are transported from the testis through the ductuli efferentes into the caput epididymidis in rete testis fluid (RTF). This fluid was first collected for analysis from conscious rams (Voglmayr, Waites & Setchell, 1966) and then from conscious bulls (Voglmayr, Larson & White, 1970) and anaesthetized wallabies (Setchell, 1970) by cannulation of the extratesticular rete through the ductuli efferentes. Rete testis fluid was then obtained from anaesthetized rats by inserting a side-hole catheter into the rete testis, 12 to 24 hr after ligating the ductuli efferentes (Tuck, Setchell, Waites & Young, 1970). Tuck et al. (1970) suggested that RTF is a mixture of two fluids; one, a highpotassium, low-protein fluid secreted in the seminiferous tubules, and the other,

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A. Bendz, N. Einer-Jensen, O. Lundgren and P. O. Janson

Summary. A miniature Geiger—Müller probe was inserted into one ovary of 8 women undergoing hysterectomy. A control probe was inserted into the other ovary of 2 of the women. Krypton-85 in 0·15 m-NaCl was infused into the adjacent utero-ovarian vein and the radioactivity was registered for 5–14 min after the infusion. An increase of radioactivity was recorded in the ovary in 5 cases. In one of the women with 2 probes, no increase in radioactivity was observed in the control ovary. The results show a local transfer of gas from the ovarian branch of the uterine vein into the adjacent ovary, which may be due to a countercurrent exchange mechanism between the vessels of the human uterine adnexa.