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Biomedical subjects

B T Donovan

Publications and source records attributed to B T Donovan.

At least 55 records · Page 3Linked to original sources
PubMed1974

Stimulation of the hypothalamus and ovulation in the guinea-pig.

1. Various methods of stimulating the hypothalamus were applied to the guinea-pig with the aim of inducing ovulation.2. Electrochemical stimulation of the hypothalamus, or gross stimulation of the brain, was ineffective.3. Electrical stimulation of the medial basal hypothalamus or rostral hypothalamus elicited gonadotrophin release.4. Despite variation of the time and intensity of stimulation, follicular luteinization was more common than the formation of new corpora lutea.5. Electrical stimulation of the medial basal hypothalamus often caused luteinization of follicles. Fewer animals responded to excitation of the rostral hypothalamus, but in those that did, ovulation occurred more frequently.6. The present observations contrast markedly with comparable studies on the rat, where both electrochemical and electrical stimulation of the hypothalamus readily induce ovulation.

Animals↗
PubMed1972

The release of prostaglandins and progestin into the utero-ovarian venous blood of guinea-pigs during the oestrous cycle and following oestrogen treatment.

1. Blood was collected from the utero-ovarian vein of guinea-pigs on days 3, 9, 10, 11, 12, 13, 14 and 15 of the oestrous cycle, and from animals injected with oestrogen over days 4-6 and used on day 7. The content of prostaglandin F(2alpha) and E(2) was determined by bio-assay and gas chromatography-mass spectrometry, and of progestin by competitive protein binding assay.2. The concentration of prostaglandin F(2alpha) on day 3 was 14.1 ng/ml.; it fell below detectable limits on day 7, but after day 11 the concentration rose to between 15.7-17.2 ng/ml. A value of 60.7 ng/ml. was recorded on day 15.3. The release of prostaglandin F(2alpha) was increased in animals pre-treated with oestrogen but was below threshold levels in similarly treated hysterectomized females.4. Prostaglandin E(2) was not detectable in blood collected on days 3, 9, 10, 11 and 12. From a threshold value of 1.1 ng/ml. on day 13, the concentration rose to 5.4 ng/ml. on day 14 and to 54.9 ng/ml. on day 15.5. The progestin concentration rose from 66 ng/ml. on day 3 to values of 80-180 ng/ml. between days 9-14. It fell to 45 ng/ml. between days 14 and 15.6. This work establishes that prostaglandin F(2alpha) is released into the utero-ovarian venous blood, and that its concentration fluctuates in the course of the oestrous cycle and can be related to changes in luteal function.

Animals↗