Assessment of bronchial responsiveness on exposure to isometric exercise during different phases of menstrual cycle: A pilot study.

Objectives: The present study was planned to assess the effects of gonadal steroids (estrogen and progesterone) on bronchial responsiveness, before and after handgrip exercise, during different phases of menstrual cycle. Materials and Methods:In this study, 30 healthy (25-40 years), non-athletic, adult female volunteers were studied. The various pulmonary function parameters (FVC, FEV 1 , PEFR, FEF 25-75% ) were recorded with a spirometer under resting conditions and then within five minutes of cessation of isometric exercise. Recordings were taken during the Menstrual phase (MP), Proliferative phase (PP), and Luteal phase (LP) of menstrual cycle and were confirmed by plasma levels of estrogen and progesterone. The oral temperature was recorded during each phase of the menstrual cycle. Results : Under resting conditions, the above-mentioned parameters did not reveal significant differences during the three phases. A significant fall was observed only in the Peak Expiratory Flow Rate (PEFR) during all the phases after handgrip, but there was a non-significant decline in the other parameters. Conclusion : By this study we conclude that the physiological changes in hormone levels during the menstrual cycle are not in themselves associated with changes in airway responsiveness before and after the handgrip test. The general fall seen in the pulmonary parameters could be due to fatigue or psychic factors.

Evaluation of the activity of receptor-operated Ca2+ channels in rat portal vein in induced hyperthyroidism.

The activity of receptor-operated Ca2+ channels (ROCCs) was studied in rat portal vein in L-thyroxine-induced experimental hyperthyroidism. The following parameters were evaluated: 1. NE-stimulated 45Ca influx. 2. CaCl2-induced contractile responses in Ca2+ free NE-stimulated tissues to calculate EC50 value of CaCl2. The NE (10(-6)mol) stimulated 45Ca influx and the mean EC50 value of CaCl2 did not differ significantly in portal veins isolated from hyperthyroid rats as compared to those of euthyroid control rats. The study revealed no significant change in the functional status of ROCCs in experimental hyperthyroidism.

Changes in serum triiodothyronine, thyroxine, estradiol-17 beta, progesterone levels and egg production in hypocholesterolemia induced Japanese quails Coturnix coturnix japanica.

Mature healthy female Japanese quails injected (i.p.) with gemfibrozil at two dose levels for 1,2,3 and 4 weeks induced hypocholesterolemia as observed by the serum cholesterol concentration which was more severe with the higher dose. Liver and ovarian cholesterol contents decreased in 3rd and 4th week of the treatment. Significant (P > 0.05) increase in serum triiodothyronine (T3) and thyroxine (T4) level were observed between 3rd and 4th week while serum estradiol-17 beta and progesterone levels declined continuously from Ist week till the termination of the treatment. The quantity and quality of the eggs produced by the treated quails were inferior. These results indicate that induction of hypocholesterolemia impaired the reproductive efficiency of quails.

Centrally mediated alpha & beta adrenoceptors controlling blood pressure in rabbits.

The effect of intracerebroventricular (icv) injection of noradrenaline (NA) on the blood pressure was studied in anaesthetised rabbits. Adrenoceptor blockers were used to study the specific adrenoceptor mediating the response. The results indicated a hypotensive response to icv injection of NA. This hypotensive response to NA was blocked by alpha-2 (yohimbine) and beta-1 (metoprolol) but not by alpha-1 (prazosin) and beta-2 (butoxamine) adrenoceptor blockers.

A study of action of norepinephrine on hypothalamic feeding centres.

Effects of intrahypothalamic and intraventricular microinjections of norepinephrine (NE) were studied in fasted albino rats. Applications of NE into ventromedial hypothalamus (VMH), medial part of lateral hypothalamus (LH) and lateral ventricle (LV) caused marked but short lasting decrease in food intake, whereas lateral part of LH was insensitive to NE administration. Decrease in water intake seemed secondary to decrease in food intake. Decrease in food intake could not be attributed to the alteration of body temperature. This study explains the mechanism of anorexigenic action of amphetamine and the mechanism of hyperphagia following destruction of the ventral noradrenergic bundle.

Gonadotrophin-induced ovulation in melengestrol acetate treated female goat.

Adult, Black Bengal goats synchronized to oestrus with Melengestrol Acetate (MGA) could be subjected to superovulation with 1000 IU of the Pregnant Mare Serum Gonadotrophin (PMSG). However, with 500 IU of PMSG higher rate of ovulation observed only in goats above one year age was not significant. Results indicate that the successful superovulation in MGA synchronized goats depend both on the dosage of the PMSG, as well as upon the age of the treated animal.