Influence of Aging and Menstrual Status on Subcutaneous Fat Cell Lipolysis.

Abstract

Aging is accompanied by inhibited fat cell mobilization of fatty acids through lipolysis, which may contribute to decreased energy expenditure in elderly subjects. However, the influence of menstrual status is unknown. To investigate the role of menstrual status on changes in lipolysis induced by aging. A longitudinal investigation with a mean 13-year interval. Ambulatory study at a clinical academic unit. Eighty-two continuously recruited women between 24 and 62 years of age and with body mass index 21 to 48 kg/m2 at first examination. Twenty-nine women continued to have normal menstruation, 42 developed irregular menstruation/menopause, and 11 had a perimenstrual/menopausal phenotype already at the first examination. Lipolysis measured as glycerol release from isolated subcutaneous fat cells incubated in vitro. On average, body weight/body fat mass levels did not change over time. In all 3 groups, aging was associated with a similar decrease in spontaneous (basal) and catecholamine-stimulated lipolysis. The latter was due to decreased signal transduction through stimulatory beta adrenoceptors and increased alpha-2-adrenoceptor-mediated antilipolytic effects. Gene microarray data from adipose tissue at baseline and follow-up (n = 53) showed that a limited set of lipolysis-linked genes, including phosphodiesterase-3B, were altered over time, but this was independent of menstrual status. Fat cell size also decreased during aging, but this could not explain the decrease in lipolysis. In women, the rate of fat cell lipolysis decreases during aging due to multiple alterations in spontaneous (basal) and catecholamine-induced lipolysis. This is independent of changes in menstrual status or fat cell size.