No abstract

Relationships among the release of prolactin, the effect of oestrogens and the proliferation of prolactin-secreting cells were studied under several experimental conditions. Administration of sulpiride or oestradiol released prolactin and stimulated cell proliferation in the anterior pituitary gland of adult male rats. Clomiphene completely abolished the rise in cell proliferation, but did not interfere with the sulpiride-induced release of prolactin. Treatment with oestradiol plus sulpiride significantly increased serum prolactin concentrations and the mitotic index compared with the sum of the stimulation produced by both drugs separately. Bromocriptine abolished the stimulatory effect of oestradiol on the serum prolactin concentration and on cell proliferation. In oestradiol- and/or sulpiride-treated rats, 80% of the cells in mitoses were lactotrophs. The remaining 20% did not stain with antisera against any of the pituitary hormones. The number of prolactin-secreting cells in the anterior pituitary gland significantly increased after the administration of oestradiol or sulpiride. The results demonstrate that treatment with sulpiride and/or oestradiol increases the proliferation and the number of lactotrophs in the anterior pituitary gland of the rat.

An antioxidant mixture (LAROTABE) was evaluated in the treatment of Graves disease. Fifty-six hyperthyroid patients were treated with methimazol (MMI) (A), LAROTABE (B), or MMI plus LAROTABE (C). According to a clinical score, improvement was obtained at 8 weeks in A and 4 weeks in B and C. Group A diminished their thyroid hormone concentration to normal levels, while patients with LAROTABE did not reduce T3 and T4 unless MMI was introduced. Hyperthyroid patients had increased malondialdehyde (MDA) content and SOD activity and decreased catalase activity compared to controls. Within group A, MDA decreased to control values while SOD was reduced 38.3% and catalase increased 21.6%. Similar results were obtained for MDA and for both enzymes after treatment with LAROTABE. Signs and symptoms of Graves disease might be related to an increase in free radicals; antioxidants could be a new therapeutic tool to improve the clinical manifestation of this illness.

—The incorporation of [3H]thymidine into nuclear DNA of rat brain progressively increased from birth until the 8th postnatal day and it was lowest in the adult brain. When isolated nuclei from brain cells were separated into a neuronal‐ and a glial‐rich fraction (composed of glial and neuroblast nuclei in young animals), the specific radioactivity of the DNA was higher in the glial‐rich fraction at all ages investigated. The incorporation of [3H]leucine into proteins of rat brain was considerably higher in the 8‐than in the 1‐day‐old rat. The greatest difference in the rate of protein synthesis between 8‐ and 1‐day‐old brain occurred in the nuclear proteins, especially those associated with DNA. There was an accumulation of protein and RNA in nuclei from brain cells from birth to the 8th postnatal day. The increased content of proteins occurred primarily in the fraction soluble in buffered saline (nuclear sap).

and hyperprolactinemia. In these rats the administration of the dopaminergic agonist bromocriptine reduces the levels of serum prolactin and the size of the pituitary gland [5, 6]. Estrogens also stimulate cell proliferation in breast tissue and the presence of estrogen receptors in breast cancer is an important sign in the degree of differentiation and an important indication of prognosis and treatment selection [7, 8]. Thus, the presence of estrogen receptors in breast cancer indicates a more differentiated tissue and a better prognosis than the absence of this protein. Furthermore the concentration of estrogen receptors in breast cancer cells contributes to the stadifi cation of breast cancer and allows making a rational decision on the usefulness of the treatment with anti-estrogen [9]. Although pituitary tumors are almost entirely histologically benign, their behavior varies considerably after surgery and / or in their response to dopaminergic agonists. Some of them are fast growing adenomas and relapse rapidly after surgery requiring treatment with dopaminergic agonists almost immediately. Others are apparently cured by surgery: prolactinemia remains within normal range and there are no signs of regrowth. There are all kinds of intermediate cases between these two above mentioned options. We have shown that dopaminergic ago-Authors