Chronic-intermittent cold stress in rats induces selective ovarian insulin resistance.

• In rat ovary chronic cold stress increases sympathetic nerve activity, modifies follicular development, and initiates a polycystic condition. To see whether there is a relationship between the previously described changes in follicular development and metabolic changes similar to those in women with polycystic ovary, we have studied the effect of chronic cold stress (4 degrees C for 3 h/day, Monday to Friday, for 4 wk) on insulin sensitivity and the effect of insulin on sympathetic ovarian activity. Although cold-stressed rats ate more than the controls, they did not gain more weight. Insulin sensitivity, determined by hyperinsulinemic-euglycemic clamp, was significantly increased in the stressed animals. Insulin in vitro increased the basal release of norepinephrine from the ovaries of control rats but not from those of stressed rats, suggesting a local neural resistance to insulin in stressed rats. The levels of mRNA and protein for IRS1 and SLC2A4 (also known as GLUT4), molecules involved in insulin signaling, decreased significantly in the ovaries but not in the muscle of stressed rats. This decrease was preferentially located in theca-interstitial cells compared with granulosa cells, indicating that theca cells (the only cells directly innervated by sympathetic nerves) are responsible for the ovarian insulin resistance found in stressed rats. These findings suggest that ovarian insulin resistance produced by chronic stress could be in part responsible for the development of the polycystic condition induced by stress.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Physiology (hsv//eng)

Nyckelord

Adrenergic Fibers

metabolism

physiology

Animals

Cold Temperature

adverse effects

Female

Glucose Transporter Type 4

genetics

metabolism

Insulin

pharmacology

Insulin Receptor Substrate Proteins

genetics

metabolism

Insulin Resistance

physiology

Muscle

Skeletal

drug effects

metabolism

Norepinephrine

metabolism

Organ Specificity

drug effects

physiology

Ovary

drug effects

innervation

metabolism

physiology

Periodicity

Polycystic Ovary Syndrome

etiology

Rats

Rats

Sprague-Dawley

Stress

Physiological

genetics

physiology

Time Factors

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)