Search Results

You are looking at 1 - 3 of 3 items for

  • Author: D. GAWLAK x
Clear All Modify Search
Free access

T. W. MISCHLER and D. GAWLAK

Summary.

The biological properties of 8-aza quinestrol (AQ) were compared to quinestrol (Q) and ethynyloestradiol (EE). AQ is an orally active oestrogenic steroid, which is taken up and released from body fat and therefore has some prolonged effects. Storage of AQ, however, was less than that reported for Q and, as a consequence, Q had considerably more prolonged action. AQwas less potent than either steroid in the immature rat uterotrophic assay. In the adult rat, AQ was less potent than Q but more potent than EE for prevention of pituitary-related responses (fertility, ovulation and ovarian hypertrophy after hemicastration). It was concluded that substitution of a nitrogen atom in the 8 position decreased both the biological and fat storage properties of Q.

Free access

SHEILA F. STEWART, D. GAWLAK and SUSAN KOPIA

Hemicastration in the rat is followed by hypertrophy of the remaining gonad (Heller, Heller & Sevringhaus, 1942), presumably as a result of increased pituitary secretion of gonadotrophins (Benson, Sorrentino & Evens, 1969). Howland (1972) recently demonstrated that caloric restriction interfered with ovarian hypertrophy and speculated that this was due to a decreased level of hypothalamic releasing factors. The present study was undertaken to determine if caloric restriction affected gonadal hypertrophy in the male as in the female.

Immature Sprague-Dawley male rats, weighing 35 to 40 g, were used since the mature male does not respond with gonadal hypertrophy when hemicastrated (Means & Hall, 1967). For comparison with the results obtained by Howland (1972), adult female rats weighing 160 to 180 g were used, but for comparison with the males, an immature female was used. Both sexes were

Free access

SHEILA F. STEWART, SUSAN KOPIA and D. L. GAWLAK

Warner-Lambert Research Institute, Morris Plains, New Jersey 07950, U.S.A. (Received 13th February 1975)

Dietary regimens have been shown to influence the secretion of gonadotrophins (Mulinos & Pomerantz, 1940; Leathem, 1958; Srebnik & Nelson, 1963), the changes occurring as the result of decreased hypothalamic content of FSH-RF and LH-RF (Piacsek & Meites, 1967) or FSH-RF activity (Negro-Vilar et al., 1971). Root & Russ (1972) demonstrated that fasting reduced serum FSH levels in intact male rats whereas Howland (1971a) reported that no change occurred in fasted female rats. Root & Russ (1972) and Ibrahim & Howland (1972) found that castration increased serum FSH levels, but the release of FSH was inhibited in the females and increased in the males when they were also fasted. A similar increase in FSH secretion in both sexes has been shown many times (Benson et al., 1969; Ibrahim & Howland, 1972; Howland & Skinner, 1973; Stewart et