Twenty-four hour profiles of growth hormone (GH) concentrations in mature female and entire male domestic pigs in comparison with mature wild boars ( Sus scrofa L.)

Abstract

Diurnal patterns of growth hormone (GH) in peripheral plasma were compared between mature German Landrace (GL) boars ( n = 6), GL sows ( n = 4) and European wild boars ( n = 5). Blood samples were drawn at 20-min intervals through indwelling jugular vein catheters for 24 h. Some of the animals were sampled repeatedly, so twelve 24-h profiles were available for GL boars, six for GL sows and seven for wild boars. The GH concentrations were determined by a specific radioimmunoassay. GL boars revealed significantly higher ( P ≤ 0.001) GH concentrations than GL sows (boars: 5.06 ± 2.34 ng ml −1; sows: 3.70 ± 1.01 ng ml −1). In GL boars a clear diurnal pattern with distinct GH pulses during daytime and a less pulsatile GH release during the night was found, whereas in females no diurnal pattern was obvious. Mean GH levels in wild boars (1.97 ± 1.03 ng ml −1) were significantly lower ( P < 0.001) than in both groups of GL pigs. The diurnal pattern of GH pulses in wild boars, however, coincided with the pattern of GH release in GL boars ( r = 0.26; n = 73; P ≤ 0.05).