Plasma Growth Hormone and Prolactin Levels in Healthy Sedentary Young Men after Short-Term Endurance Training under Hot Environment / NIVOI PLAZMINOG HORMONA RASTA I PROKLATINA KOD ZDRAVIH SEDENTARNIH MLADIH LJUDI NAKON KRATKOTRAJNOG TRENINGA U TOPLOM OKRUŽENJU

Pituitary hormones play an important role energy expenditure and body temperature regulation during exercise. The aim of the stu¬dy was to investigate the effect of two different endurance training in ambient temperature (30.76 ± 1.71oC and 57.92 ± 5.80% r.h.) on plasma growth hormone (GH) and prolactin (PRL) levels in non-trained healthy subjects. Twenty-four untrained healthy men participated in an 8-wk progressive two different endurance-training program. Subjects were divided into two groups: an in¬ter¬val running group (IR), and continuous running group (CR). Both groups were performed 3 days/wk. Growth hormone, PRL and VO2max levels were assessed at the beginning and the end of the training period. Body temperature (TB) was also measured at the be¬ginning and immediately after each training. The exercise type affected plasma PRL (8.52 vs. 6.50 ng/ml IR and CT groups, P0.38). Plasma GH level at the end of training pro¬gram increased from 0.42 to 1.48 ng/ml and 0.58 to 0.67 ng/ml for IR and CR groups. Expectedly, both training types increased TB, at a greater rate for IR group than CR group. In conclusion, an 8-wk regular exercise result in an increase in plasma PRL level, with¬out altering plasma GH level, which accompanied by elevated body temperature, regardless of the individual’s sporting rou¬ti¬ne. These suggest that untrained individuals could benefit from a regular exercise program as much as those doing the routine sport. Hipofizini hormini imaju važnu ulogu u potrošnji energije i regulaciji tjelesne temperature tokom vježbanja. Cilj istraživanja bio je da se ispita uticaj dva različita treninga izdržljivosti u sobnoj temperaturi (30.76 ± 1.71oC i 57.92 ± 5.80% r.h.) na nivo plazminog hormona rasta (GH) i proklatina (PRL) kod neobučenih zdravih ispitanika. Dvadesetčetvorica neobučenih zdravih muškaraca učestvovali su u dva različita osmonedjeljna progresivna programa treninga izdržljivosti. Učesnici su bili podijeljeni u dvije grupe: grupu koja je povremeno trčala (IR), i grupu koja je neprestano trčala (CR). Obije grupe su izvodile vježbe 3 dana nedjeljno. Nivo hormona rasta, PRL-a i VO2max procjenjivan je na početku i na kraju perioda treniranja. Tjelesna temperature (TB), takođe je mjerena na početku svakog treninga i odmah nakon istih. Ovaj tip vježbe uticao je na plazmin PRL (8.52 naspram 6.50 ng/ml IR i CT grupe, P < 0.02) ali nije mijenjao nivoe plazminog GH (0.95 naspram 0.63 ng/ml IR i CT grupe, P>0.38). Nivo plazminog GH na kraju pro