Oestrogens and insulin secretion

Regulation of prolactin secretion by oestrogens: physiological and pathological significance.

Prolactin is unique among the anterior pituitary hormones in that it is under tonic inhibitory control by the hypothalamus. There is much evidence that the major prolactin inhibitory factor is dopamine [l-31. However, there are a number of physiological stimuli of prolactin secretion which can ‘override’ the effect of dopamine and one of the most important of these is oestrogen. Oestrogens are ...

Insulin Secretion and Actions

Aging and insulin secretion.

Glucose tolerance progressively declines with age, and there is a high prevalence of type 2 diabetes and postchallenge hyperglycemia in the older population. Age-related glucose intolerance in humans is often accompanied by insulin resistance, but circulating insulin levels are similar to those of younger people. Under some conditions of hyperglycemic challenge, insulin levels are lower in olde...

Bromocriptine and insulin secretion.

The dopaminergic drug bromocriptine inhibited the release of insulin from isolated mouse pancreatic islets. The effect was counteracted by haloperidol or pimozide. It is suggested that insulin release may be inhibited through activation of D-2 dopaminergic receptors in the pancreatic beta-cells.

Insulin Secretion

Insulin is secreted from the -cells of the pancreatic islets by Ca 2 -dependent exocytosis of large dense core vesicles (LDCVs) (Ämmälä et al., 1993), a process that is triggered by glucose-induced electrical activity (Henquin and Meissner, 1984). In response to a step elevation of glucose, insulin secretion follows a characteristic biphasic time course (Curry et al., 1968): an initial transien...