Effect of radio-thyroidectomy and thyroid hormone replacement therapy on cardiac protein kinase activity and ATP hydrolysis.

The regulatory effect of thyroid hormone on cardiac protein kinase activity and ATP hydrolysis was studied in developing rats. Experimental hypothyroidism induced by a single intraperitoneal injection of 200 muCi of 131I led to a significant impairment of body and heart growth and elevated the activity of membrane-bound protein kinase (measured in the absence of cyclic AMP). However, a slight (11%) but statistically non-significant decrease was observed in soluble protein kinase activity in hearts of hypothyroid rats.

Biological activity of some steroidal compounds in the adult and larval frogs.

Four steroids were tested for their biological activity, using the sex-steroid-dependent redevelopment of the secondary sex characteristics in adult frogs and gonadal sex differentiation in larval frogs as end points. In adult frogs, 19-norprogesterone and 6-chloro-17alpha-hydroxy-4, 6-pregnadiene-3,20-dione had antiandrogenic and antiestrogenic effects. 2alpha, 17alpha-Dimethyl-DHT and 2alpha-methyl-DHT were potent androgens and effective antiestrogens.

Ontogenic pattern of dopamine, acetylcholine, and acetylcholinesterase in the brains of normal and hypothyroid rats.

The influence of neonatal thyroidectomy (Tx) on developmental changes in dopamine (DA), acetylcholine (ACh), and acetylcholinesterase (AChE) was studied in the whole brain of rats. In control animals, brain levels of ACh gradually increased and attained adult values at the 70th day. In contrast, AChE activity showed a rapid increase between the 7th and 30th days.

The function of fat bodies in relation to the hypothalamo-hypophyseal-gonadal axis in the frog, Rana esculenta.

In this study the authors have tried to furnish experimental support for the importance of fat bodies in the normal functioning of the hypothalamo-hypophyseal-gonadal system of the male frog, Rana esculenta. These experiments have shown a hypothalamo-hypophyseal control of the mobilization of fat body contents, directly involved in the control of testicular activity. Furthermore it is proposed that the fat body contents are released into the testis through direct vascular contacts between the two organs.

Spasmolytic constituents of Cedrus deodara (Roxb.) Loud: pharmacological evaluation of himachalol.

Himachalol has been identified as the major antispasmodic constituent in the wood of Cedrus deodara. The pharmacological studies of himachalol on various isolated smooth muscles (guinea pig ileum, rabbit jejunum, rat uterus, and guinea pig seminal vesicle) and against different agonists (acetylcholine, histamine, serotonin, nicotine, and barium chloride) indicated spasmolytic activity similar to that of papaverine. It was a more potent antagonist of barium chloride-induced spasm of guinea pig ileum than papaverine but less effective in reverting a similar spasm of rabbit jejunum and had no relaxing effect alone.

Effect of chronic cadmium treatment on rat adrenal catecholamines.

Daily intraperitoneal injection of cadmium chloride (1 mg/kg) for 45 days significantly increased adrenal weights and augmented the levels of adrenal norepinephrine and epinephrine as well as the activity of adrenal tyrosine hydroxylase. Discontinuation of the heavy metal treatment for 28 days, in rats previously injected with cadmium for 45 days, restored the activity of tyrosine hydroxylase as well as the amount of norepinephrine and epinephrine. In contrast, adrenal weights were restored only partially following the withdrawal of cadmium treatment.